# ONNX: External Data Symlink Traversal

Advisory record · `GHSA-p433-9wv8-28xj`

- **Identifiers:** `GHSA-p433-9wv8-28xj` · `CVE-2026-34447` · `PYSEC-2026-104`
- **State:** Confirmed
- **Severity:** CVSS 5.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-22](https://cwe.mitre.org/data/definitions/22.html) · [CWE-61](https://cwe.mitre.org/data/definitions/61.html)
- **Tags:** [Path traversal](https://agentprime.io/advisories/tag/path-traversal.md) · [CWE-61](https://agentprime.io/advisories/tag/cwe-61.md)
- **Published:** 1 Apr 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 1 Apr 2026, 21:14 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `onnx` (PyPI): affected `<1.21.0`; fixed in `1.21.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> GHSA-p433-9wv8-28xj: ONNX versions before 1.21.0 are affected by a symlink traversal flaw in external data loading. A model whose external data path resolves to a symlink pointing to a file outside the model directory can cause that outside file to be read, exposing its contents. Upgrade onnx to version 1.21.0 or later.

Written 5 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.5 Medium, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0026, the 17th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:34 UTC: First seen by agentprime
- 31 Oct 2026, 14:34 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-p433-9wv8-28xj)

## Sources

- [GitHub Advisory Database: GHSA-p433-9wv8-28xj](https://github.com/advisories/GHSA-p433-9wv8-28xj)
- [OSV: GHSA-p433-9wv8-28xj](https://osv.dev/vulnerability/GHSA-p433-9wv8-28xj)
- <https://github.com/onnx/onnx/security/advisories/GHSA-p433-9wv8-28xj>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-34447>
- <https://github.com/onnx/onnx>
- <https://github.com/pypa/advisory-database/tree/main/vulns/onnx/PYSEC-2026-104.yaml>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-p433-9wv8-28xj>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-p433-9wv8-28xj/>. Everything for agents: <https://agentprime.io/llms.txt>.